European Journal of Molecular& Clinical Medicine ISSN2515-8260 Volume08, Issue 04, 2021 457 Allergic Rhinitis in Relation to Gut Microbiota Composition among School-Aged Patients Samir Sourour 1 , Mahmoud Diab 1 , Rania M. Amer 2 , Tarek Abdelmouty 1 , Gehan A. Elshenawy 2 , Saeid Abdelmonaem 1 1 Department of Otorhinolaryngology, Faculty of Medicine-Zagazig University, Egypt 2 Department of Medical Microbiology and Immunology, Faculty of Medicine, Zagazig University, Egypt Corresponding author: Mahmoud Mostafa Diab, Email: mahmouddiab63@yahoo.com Abstract Background: Allergic rhinitis (AR) is one of the most globally commondiseases and usually persists throughout life. First-line drugs can be successfully used to control AR. However, once these medications are terminated, the majority of AR patients will reappear the symptoms of AR within a brief period. Thus, these medications do not appear to exert a long-term effect on the baseline Total Nasal Symptom Score.To study the relationship between the gut microbiota types and allergic rhinitis. Patients and Methods: This case control study was carried out on 52 school-aged patients presented at Oto-rhino-laryngology, Head and Neck (ORL- HNS) Department and Microbiology and Immunology department at Zagazig University. The patients were classified into 2 groups: Allergic rhinitis group: 26 individuals with allergic rhinitis Control group: 26 individuals without allergic rhinitis. All patients in this study were subjected to the personal history taking, physical examination and laboratory investigations including: eosinophilic count, skin prick tests (SPT) for common perennial and seasonal allergens, measurement of (total Ig E) and identifing bacteria (lactobacillus and bacteroides) by SYBR Green real time PCR. Results: Age was distributed as 11.19±3.26 and 11.65±3.24 respectively between case and control with no significant difference between groups. Mean disease duration was 6.15±2.01, the majority were Intermittent and mild regard classification also the majority were trigger by inhalation. Skin prick test among cases group showed majority were house dust and date palm pollens. Absolute eosinophils counting was significantly higher among cases compared to control one. Cases were significantly higher regard IgE distribution. Lactic acid bacteria RNA was significantly higher among control group compared to cases group while Bacteroid bacteria RNA was significantly higher among cases group compared to control group. Conclusion: Lactic acid bacteria in gut microbiota of school-aged individuals may influence sensitization to different allergens. Keywords: Allergic Rhinitis; Gut Microbiota; SYBR PCR; Ig E; Skin prick test INTRODUCTION Allergic rhinitis is characterized by nasal congestion, rhinorrhea, sneezing, itching of the nose, and/or postnasal drainage. Additionally, airway hypersensitivity may